All living things are on Earth are carbon based life forms, carbon is the essential element for all living things.

On Earth, inorganic carbon (CO2) can be found:

1. in the atmosphere.
2. dissolved in oceans.

Organic carbon is found in only one place:

1. as part of the bodies that are living things.



– conduct photosynthesis; use light energy from the sun and water from the soil or ocean to combine CO2 into complex organic molecules

The Chrysalids: Author, Style, Geographical, Social, Atmosphere, Theme

6 CO2 + 6H2O + light energy -> C6H12O6 (glucose) + 6 O2

– includes land and aquatic plants, algae and some bacteria

All living things:

– perform cellular respiration, which converts glucose into CO2 and H2O molecules

C6H12O6 (glucose) + 6 O2 -> 6 CO2 + 6 H2O + energy for cell

Complementary Processes

– the carbon that they use is repeatedly cycled through both processes
– this cycling of carbon is called the Carbon Cycle

Carbon Reservoirs

Reservoirs of Inorganic Carbon:

Cell Reactions and Energy

– atmosphere (CO2 gas; 0.03%)
– oceans (dissolved in water or part of the shells of living things)
– Earth’s crust (rocks)

Reservoirs of Organic Carbon:

– bodies of living things (released by decomposers when organism dies)
– bogs (little decomposition; form coal)
– ocean floors (little decomposition; form oil)


  1. Good info – picture needs chemical formula correction.

    Co is cobalt – should be CO2 for carbon dioxide as in text
    (subscript 2 correct – often done wrong as superscript)

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